A guide-magnetic-field-free modular array diode for efficient electron beam pumping in excimer lasers

Diode is one of the most important elements in the excimer laser, which is used to generate and accelerate electron beams to pump laser. Traditional large-area electron beam diodes for excimer laser pumping rely on guiding magnetic fields to confine the electron beam, which increases system volume and complexity and limits modularization. This paper presents and validates a magnetic-field-free modular array diode. Driven by modular pulsed power units and employing strip-shaped array cathodes, the diode is designed by combining field-enhanced space-charge-limited flow theory with particle-in-cell simulations. This approach optimizes the matching between the cathode width and the anode hibachi aperture to minimize beam interception on the grid and achieve impedance matching of ∼50 Ω with the driver. At an accelerating voltage of 150 kV, experiments demonstrate an electron beam energy deposition efficiency of 38.2% and a beam transport efficiency of 39.5%, with deviations of less than 10% from Monte Carlo simulations. This method provides a universal framework for designing efficient and compact electron beam diodes under magnetically unconfined or weakly confined conditions, paving a promising path toward advanced high-power excimer lasers for inertial confinement fusion.